1. Field of the Invention
The present invention relates to a method for manufacturing an organic EL display device, and a film thickness measuring device.
2. Description of the Related Art
In a process of manufacturing an organic EL display device, in some cases, vapor deposition may proceed while the thickness of a thin film is measured with a film thickness measuring device. For example, a thin film of a metal such as magnesium (Mg) may be used along with a transparent conductive material, as an electrode material of the organic EL display device. The thickness of the metal film has an influence on light emission and therefore needs to be controlled with high accuracy. Thus, the metal film may be deposited while the thickness of the metal film is measured with a film thickness measuring device.
As such a film thickness measuring device, a film thickness measuring device utilizing a crystal oscillator is known (for example, JP 2007-024909 A). Since the crystal oscillator is installed to be exposed into a deposition chamber, a thin film is also formed on the surface of the crystal oscillator in the vapor deposition process on the substrate of the organic EL display device. As the thin film is formed on the surface of the crystal oscillator, the natural frequency of the crystal oscillator changes. Therefore, by measuring the natural frequency of the crystal oscillator, the thickness of the thin film on the crystal oscillator is calculated. On the basis of the thickness of the thin film on the crystal oscillator, the thickness of the thin film formed on the substrate of the organic EL device is calculated.